1) Field of the Invention
The invention herein relates to circuit board diagnostic and examination utilities, specifically an improved structure composite-type test fixture.
2) Description of the Prior Art
After various electronic components are soldered to a circuit board, it must undergo testing to determine if there are shorts among the traces and junctions. The industry now utilizes a circuit board testing method (see FIG. 1) consisting of a plurality of probes 2 disposed in the upper surface of a fixture 1, with the said plurality of probes 2 situated such that they match the positions of connection points along the bottom surface of a circuit board unit under test 3. The fixture 1 has a rectangular base 11 and latched connectors 12 are installed along the perimeter of the said base 11; each latched connector 12 must be in electrical continuity with the probes 2 so that the latched connectors 12 can be utilized for interfacing the flat cable (not shown in the drawings) of a circuit board tester.
When testing a circuit board, the flat cable of the circuit board tester is plugged into a latched connector(s) 12 and the circuit board unit under test 3 is aligned with the probes 2 on the fixture 1. After the probes 2 contact the component leads along the bottom surface of the circuit board unit under test 3, the circuit board tester indicates whether there are trace and/or junction short circuits the circuit board unit under test 3.
The said fixture 1 that provides for circuit board testing is not a mass produced item, but a dedicated utility for a particular type of circuit. The construction process of the said fixture consists of first drilling holes in the probe board 13 that are aligned with the traces and connection points of the circuit board under test 3 and then later inserting probe barrels 5 that each ensleeve a probe 2 (as shown in FIG. 2 and FIG. 3) in every hole; of course, before the said probe barrels 5 are inserted into the holes, the wires 52 at their trailing ends must be coupled to the latched connector 12 (as shown in FIG. 4) and finally the probes 2 are admitted into the probe barrels 5.
As such, a circuit board testing fixture 1 set requires the manual coupling of the trailing end wires 52 of each probe barrel 5 to the latched connector 12, with each complete fixture 1 necessitating the securing of 200 to 300 or more wires such that connection in mass volume consumes extremely long periods of labor which results in rather high production costs. Furthermore, if the connection of the wire 52 is not executed carefully, contact between adjacent wires may cause short circuits that affect test results.
Furthermore, the internal structure of the said probes 2 also consists of a spring 4 that compresses and decompresses such that when the circuit board unit under test 3 is held down during examination, the probes 2 contact the connection points on the bottom surface of the circuit board unit under test 3. However, the said probe 2 itself is very small and, therefore, the spring 4 at the interior section not only involves extremely high technology, but is also troublesome and difficult to fabricate, resulting in steeper overall probe 2 and fixture 1 production costs. Naturally, since the said spring 4 is also diminutive, service life is shorter and, furthermore, its high susceptibility to wear directly influences test results. Thus, to ensure test result accuracy, probes 2 utilized by the fixture 1 must be replaced on a regular basis, a task that is overly troublesome, inconvenient, and uneconomical.
The primary objective of the invention herein is to provide an improved structure composite-type test fixture that improves upon the said shortcomings and which is simple to fabricate to thereby lower production costs and effectively raise testing accuracy.